Health Canada reviewing possible safety concerns with certain long-term antiplatelet (blood thinner) therapy; Benefits of treatment still outweigh potential risks

Issue

Health Canada is aware of and will be reviewing new evidence on the safety of long-term use of the prescription blood-thinners clopidogrel (Plavix) and prasugrel (Effient).

Clopidogrel and prasugrel reduce the risk of blood clots in patients who have had a heart attack, stroke or related blood clotting diseases. Dual antiplatelet therapy is the use of a blood thinner in combination with ASA (acetylsalicylic acid or Aspirin). It is commonly used following coronary stent implantation to reduce the risk of blood clots. Coronary stents are tiny tubes that are implanted in narrow or weak heart arteries to maintain blood flow to the heart.

It is important to note that Health Canada has not reached new conclusions or made recommendations regarding clopidogrel or prasugrel safety at this time. The benefits of clopidogrel and prasugrel in protecting against blood clots continue to outweigh their risks when used as directed.

The new evidence is from the Dual Antiplatelet Therapy (DAPT) Study, a large-scale, multi-national clinical trial that evaluated 12 versus 30 months of clopidogrel or prasugrel use with ASA, known as dual antiplatelet therapy. The study looked at how these drugs can prevent blood clots in patients with coronary stents. Its findings were recently published in the New England Journal of Medicine.

Health Canada is evaluating preliminary information from the study, which found that 30 months of dual antiplatelet therapy was beneficial in reducing blood clots and heart attacks relative to 12 months, but saw an increase in deaths due to non-cardiovascular causes in the 30-month group versus the 12-month group.

Health Canada will continue to evaluate the available information from this trial along with other information, and is aware of the recent communication issued by the U.S. Food and Drug Administration. Health Canada will take appropriate action based on the results of the review once it is complete, including communicating new safety information to health professionals and Canadians as necessary.

Patients with questions or concerns about their dual antiplatelet therapy should talk to their doctor.  Patients should not stop using clopidogrel and prasugrel unless on the advice of their healthcare professional. Stopping treatment may increase the risk of blood clots, which can be fatal.